CMS-1951 New ContentForm PoC
Separated each FormItem type into own modules for a better overview.
CMS-1951 New ContentForm PoC
Moved common code between a Input and FormItemSet regarding occurrence logic into FormItemOccurrence and FormItemOccurrences
CMS-1951 New ContentForm PoC
Added methods minimumReached and maximumReached on Occurrences.